I guess I'll throw in my quick two cents since I've been watching the show since '98.
The main reason I even watch the show is because it's the extremely rare case in the realm of videogame-based anime that actually remains solidly grounded to the content of the videogame that it's based on. This is not hard since the games always star "you" as the main Trainer, so the game itself has a somewhat open ended story although there is the main game to push through which is where much of the game's plot lies. As someone who's been playing the games hardcore since they came stateside in '98, it amuses me to watch this show because it actually fleshes out the games' world in a unique way, staying so very close to the games' original portrayal of its gameplay mechanics, characters, locales, etc. Where the games are the core canon material, the anime is a more fully-realized "real world" version of the game.
Reflecting on the original Kanto story arc, I guess I can look back on it nostalgically. But at the same time, I can see the major flaws - the animation was clearly not up to par, there was lots of lame filler episodes, and the plots for each episode were generally repetitive. But, like I said, it amused me to see the world in the games being fleshed out and I just kind of accepted it at face value. After all, the anime is just a big advertising vehicle for the games in the first place. But at the same time, the anime really complemented the games and really got you interested in playing. I guess in my head, as I played the games, I could pretend that I was another Trainer out there in the anime who could theoretically cross paths with Ash and co. or Team Rocket. And that's exactly what the game producers and the anime producers wanted you to think. I love that the games and the anime are produced in tandem like this. It perpetuates that thinking of being a Trainer in the game while experiencing it closer to home through the anime every week.
Watching it today, I'm glad that the anime has grown alongside the games, and in that vein the audience as well. While we still follow Ash's exploits (albeit the fact that he hasn't aged in over ten years), it's nice to see that they're challenging him with slightly fresher, more interesting story devices and characters, keeping the newer audience and longtime Pok